The format '%{family|delete( )}' expands to family values with space removed.
The format '%{family|translate( ,-)}' expands to family values with space
replaced by dash. Multiple chars are supported, like tr(1).
The format '%{family|escape(\\ )}' expands to family values with space
escaped using backslash.
The format '%{family|downcase}' for example prints the lowercase of
the family element. Three converters are defined right now:
'downcase', 'basename', and 'dirname'.
The conditional '%{?elt1,elt2,!elt3{expr1}{expr2}}' will evaluate
expr1 if elt1 and elt2 exist in pattern and elt3 doesn't exist, and
expr2 otherwise. The '{expr2}' part is optional.
The filtering, '%{+elt1,elt2,elt3{subexpr}}' will evaluate subexpr
with a pattern only having the listed elements from the surrounding
pattern.
The deletion, '%{-elt1,elt2,elt3{subexpr}}' will evaluate subexpr
with a the surrounding pattern sans the listed elements.
Behdad Esfahbod